William Atkins
Saturday, 21 February 2009 00:14
Science -
Space
Page 3 of 4
Gamma-ray bursts (GRBs) are the brightest, most energetic explosions seen in the Universe. Astronomers think that they occur when massive stars in distant galazies deplete their reserves of materials (and, thus, energy). When this happens, the star begins to collapse onto itself, eventually dying while turning itself into a black hole.
However, before it becomes a black hole, jets are ejected out from its core at speeds approaching the speed of light (which, in the vacuum of space, is a speed of about 186,400 miles per second (300,000 kilometers per second).
Compared to a car running down the highway at about 70 miles per hour (112 kilometers per hour), that’s about 671,040,000 miles per hour (1,080,000,000 kilometers per hour).
As the jets are expelled out into outer space, they interact with gases left over from the dying star. The gases and the jets react with each other (scientists aren’t sure how) to produce bright afterglows that eventually fade away.
Then, a team lead by Jochen Greiner (Max Planck Institute for Extraterrestrial Physics, in Garching, Germany), recorded the fading afterglow of the explosion. Greiner was also one of the authors of the
Science article.
The NASA article stated,
“The team simultaneously captured the field in seven wavelengths using the Gamma-Ray Burst Optical/Near-Infrared Detector, or GROND, on the 2.2-meter telescope at the European Southern Observatory in La Silla, Chile. In certain colors, the brightness of a distant object shows a characteristic drop-off caused by intervening gas clouds."
And,
"The farther away the object is, the redder the wavelength where this fade-out occurs. This gives astronomers a quick estimate of the object's distance. The team's follow-up observations established that the explosion took place 12.2 billion light-years away.”
Page four concludes.
